1. Field of the Invention
The present invention relates to a machine for removing an old track and laying a new track on a ballast bed having a shoulder, each track being comprised of rails fastened to ties, which comprises an elongated machine frame extending in a longitudinal direction and supported on undercarriages for mobility in an operating direction, a device for receiving ties of the old track mounted on the machine frame, a device for planing the ballast bed mounted on the machine frame, the planing device comprising a planing shield extending transversely to the machine frame, and a device for laying ties of the new track mounted on the machine frame.
2. Description of the Prior Art
Such a track renewal machine is known, for example, from U.S. Pat. No. 5,357,867. During the continuous advancement of the machine, the ties of the old track are removed and ballast is excavated from the exposed cribs by an endless excavating chain. A trailing, vertically adjustable V-shaped ballast plow then planes the ballast bed for preparing the ballast bed for the subsequent laying of the ties of the new track.
It is known from European patent publication No. 0 085 790 to mount a rotating screw conveyor ahead of a planing shield to convey ballast to a conveyor band for removal after a track section has been lifted off the ballast bed to expose the same.
Such a combination of a planing shield and screw conveyor is also known from German patent No. 3,528,152. In this track renewal machine, ballast is continuously conveyed to a conveyor band extending in the longitudinal direction of the machine while the track is raised off the ballast bed and the ballast is thus displaced in the longitudinal direction